The electronic one's are sold by a company called "Nano Tekon" here. http://www.nanotekhi.com/
Many hotels and resturants had then installed.
Many good reports.
We don't have hard water here, but we do have lots of calcium.
I'm sure they work the same as magnets. How else would they work????
I'm thinking if it's something that simple, wouldn't everyone have it???
The magnet on the fuel line has been around for as long as I can remember.
Some people swear by it.
If it make them happy, more power to them.